Electronic systems including two-dimensional material structures

ABSTRACT

A method of forming a semiconductor device structure comprises forming at least one 2D material over a substrate. The at least one 2D material is treated with at least one laser beam having a frequency of electromagnetic radiation corresponding to a resonant frequency of crystalline defects within the at least one 2D material to selectively energize and remove the crystalline defects from the at least one 2D material. Additional methods of forming a semiconductor device structure, and related semiconductor device structures, semiconductor devices, and electronic systems are also described.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/986,129, filed May 22, 2018, which will issue as U.S. Pat. No.11,393,687 on Jul. 19, 2022, which is a divisional of U.S. patentapplication Ser. No. 15/253,454, filed Aug. 31, 2016, now U.S. Pat. No.9,991,122, issued Jun. 5, 2018, the disclosure of each of which ishereby incorporated herein in its entirety by this reference.

TECHNICAL FIELD

Embodiments of the disclosure relate to the field of semiconductordevice design and fabrication. More specifically, embodiments of thedisclosure relate to methods of forming semiconductor device structuresincluding two-dimensional material structures, and to relatedsemiconductor device structures, semiconductor devices, and electronicsystems.

BACKGROUND

Two-dimensional (2D) materials are currently being investigated for usein various semiconductor devices. As used herein, a “two-dimensionalmaterial” or “2D material” refers to a crystalline material formed ofand including a single (e.g., only one) monolayer of units (e.g., atoms,molecules) bonded together through intramolecular forces (e.g., covalentbonds). Adjacent 2D materials of a structure (e.g., a stack structure)including multiple 2D materials are coupled to one another through oneor more intermolecular forces (e.g., Van der Waals forces). Put anotherway, units (e.g., atoms, molecules) of a single 2D material are coupledto one another through intramolecular forces, and may be coupled tounits (e.g., atoms, molecules) of a second 2D material adjacent (e.g.,thereover, thereunder) thereto (if any) through intermolecular forces.The thin structure of 2D materials, along with a direct band gap in thevisible portion of the electromagnetic spectrum, suggests that 2Dmaterials are suitable for use in a wide variety of digital electronicdevices and optoelectronic devices.

Unfortunately, problems associated with conventionally forming 2Dmaterials can reduce the performance and reliability of semiconductordevices (e.g., digital electronic devices, optoelectronic devices) intowhich the 2D materials are incorporated. For example, conventionalmethods of forming 2D materials can result in significant crystallinedefects within the 2D materials that can negatively impact theproperties of semiconductor device structures and semiconductor devicesincluding the 2D materials. For example, conventionally formed 2Dmaterials can exhibit undesirable interstitial and vacancy defects, suchas those described by Haldar, S., et al., “A systematic study ofstructural, electronic and optical properties of atomic scale defects in2D transition metal dichalcogenides MX₂ (M=Mo,W; X═S, Se, Te),” Phys.Rev. B 92, 2015. Such crystalline defects can effectuate non-uniformlocal electron densities, current leakage, and shallow subthresholdslope in the 2D materials, resulting in unacceptable semiconductordevice variation.

It would, therefore, be desirable to have improved methods of forming 2Dmaterials permitting the fabrication of semiconductor device structuresand semiconductor devices having improved performance characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross-sectional view of a semiconductor devicestructure, in accordance with embodiments of the disclosure.

FIG. 2 is a graph illustrating vibrational spectra for acrystalline-defect-free (“perfect”) form of molybdenum disulfide (MoS₂)and a crystalline-defect-laden (“defective”) form of MoS₂.

FIG. 3 is a schematic block diagram of an electronic system, inaccordance with embodiments of the disclosure.

DETAILED DESCRIPTION

Methods of forming semiconductor device structures including 2D materialstructures are disclosed, as are related semiconductor devicestructures, semiconductor devices, and electronic systems. In someembodiments, a method of forming a semiconductor device structureincludes forming at least one 2D material on or over a substrate, andsubjecting the 2D material to at least one laser treatment process toselectively energize, mobilize, and at least partially (e.g.,substantially) eliminate crystalline defects (e.g., interstitialdefects, vacancy defects) within the 2D material. The laser treatmentprocess includes selecting at least one frequency of electromagneticradiation to expose the 2D material to at least partially based on acomparison of vibrational spectra for a crystalline-defect-free form ofthe 2D material and a crystalline-defect-laden form of the 2D material,and then exposing the 2D material to the selected frequency (orfrequencies) of radiation during and/or after the formation of the 2Dmaterial on or over the substrate. The frequency (or frequencies) ofelectromagnetic radiation may be selected by identifying mutual (e.g.,common, shared) resonant frequencies along the vibrational spectra wherethere is a difference between the resonant peak intensities of thecrystalline-defect-free form of the 2D material and thecrystalline-defect-laden form of the 2D material. The at least oneselected frequency of electromagnetic radiation may directly correspondto (e.g., be substantially the same as, such as exactly the same as) oneor more of such mutual resonant frequencies. Optionally, one or more ofa thermal annealing process and a remote plasma treatment process may beused in conjunction with the laser treatment process. For example, atleast one thermal annealing process may be performed before, during,and/or after the laser treatment process to assist with or at leastpartially facilitate the removal of crystalline defects from the 2Dmaterial. The methods of the disclosure may efficiently reduce or eveneliminate a crystalline defect density within the 2D material to form a2D material structure having enhanced electrically properties ascompared to conventional 2D material structures formed without the useof the methods of the disclosure.

The following description provides specific details, such as materialcompositions and processing conditions, in order to provide a thoroughdescription of embodiments of the present disclosure. However, a personof ordinary skill in the art would understand that the embodiments ofthe present disclosure may be practiced without employing these specificdetails. Indeed, the embodiments of the present disclosure may bepracticed in conjunction with conventional semiconductor fabricationtechniques employed in the industry. In addition, the descriptionprovided below does not form a complete process flow for manufacturing asemiconductor device (e.g., a memory device). The semiconductor devicestructures described below do not form a complete semiconductor device.Only those process acts and structures necessary to understand theembodiments of the present disclosure are described in detail below.Additional acts to form a complete semiconductor device from thesemiconductor device structures may be performed by conventionalfabrication techniques.

Drawings presented herein are for illustrative purposes only, and arenot meant to be actual views of any particular material, component,structure, device, or system. Variations from the shapes depicted in thedrawings as a result, for example, of manufacturing techniques and/ortolerances, are to be expected. Thus, embodiments described herein arenot to be construed as being limited to the particular shapes or regionsas illustrated, but include deviations in shapes that result, forexample, from manufacturing. For example, a region illustrated ordescribed as box-shaped may have rough and/or nonlinear features, and aregion illustrated or described as round may include some rough and/orlinear features. Moreover, sharp angles that are illustrated may berounded, and vice versa. Thus, the regions illustrated in the figuresare schematic in nature, and their shapes are not intended to illustratethe precise shape of a region and do not limit the scope of the presentclaims. The drawings are not necessarily to scale. Additionally,elements common between figures may retain the same numericaldesignation.

As used herein, the terms “vertical,” “longitudinal,” “horizontal,” and“lateral” are in reference to a major plane of a structure and are notnecessarily defined by earth's gravitational field. A “horizontal” or“lateral” direction is a direction that is substantially parallel to themajor plane of the structure, while a “vertical” or “longitudinal”direction is a direction that is substantially perpendicular to themajor plane of the structure. The major plane of the structure isdefined by a surface of the structure having a relatively large areacompared to other surfaces of the structure.

As used herein, spatially relative terms, such as “beneath,” “below,”“lower,” “bottom,” “above,” “upper,” “top,” “front,” “rear,” “left,”“right,” and the like, may be used for ease of description to describeone element's or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. Unless otherwise specified,the spatially relative terms are intended to encompass differentorientations of the materials in addition to the orientation depicted inthe figures. For example, if materials in the figures are inverted,elements described as “below” or “beneath” or “under” or “on bottom of”other elements or features would then be oriented “above” or “on top of”the other elements or features. Thus, the term “below” can encompassboth an orientation of above and below, depending on the context inwhich the term is used, which will be evident to one of ordinary skillin the art. The materials may be otherwise oriented (e.g., rotated 90degrees, inverted, flipped) and the spatially relative descriptors usedherein interpreted accordingly.

As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

As used herein, the term “configured” refers to a size, shape, materialcomposition, and arrangement of one or more of at least one structureand at least one apparatus facilitating operation of one or more of thestructure and the apparatus in a pre-determined way.

As used herein, the phrase “coupled to” refers to structures operativelyconnected with each other, such as electrically connected through adirect ohmic connection or through an indirect connection (e.g., viaanother structure).

As used herein, the term “substantially” in reference to a givenparameter, property, or condition means and includes to a degree thatone of ordinary skill in the art would understand that the givenparameter, property, or condition is met with a degree of variance, suchas within acceptable manufacturing tolerances. By way of example,depending on the particular parameter, property, or condition that issubstantially met, the parameter, property, or condition may be at least90.0% met, at least 95.0% met, at least 99.0% met, or even at least99.9% met.

As used herein, the term “about” in reference to a given parameter isinclusive of the stated value and has the meaning dictated by thecontext (e.g., it includes the degree of error associated withmeasurement of the given parameter).

An embodiment of the disclosure will now be described with reference toFIG. 1, which illustrates a semiconductor device structure 100 includinga substrate 102 and a 2D material structure 104 on or over the substrate102. While FIG. 1 depicts a particular configuration of thesemiconductor device structure 100, one of ordinary skill in the artwill appreciate that different semiconductor device structureconfigurations (e.g., shapes, sizes, etc.) are known in the art and thatmay be adapted to be employed in embodiments of the disclosure. FIG. 1illustrates just one non-limiting example of the semiconductor devicestructure 100.

The substrate 102 may comprise any base material or construction uponwhich additional materials may be formed. The substrate 102 may be asemiconductor substrate, a base semiconductor material on a supportingstructure, a metal electrode, or a semiconductor substrate having one ormore materials, structures, or regions formed thereon. The substrate 102may be a conventional silicon substrate or other bulk substratecomprising a layer of semiconductive material. As used herein, the term“bulk substrate” means and includes not only silicon wafers, but alsosilicon-on-insulator (SOI) substrates, such as silicon-on-sapphire (SOS)substrates and silicon-on-glass (SOG) substrates, epitaxial layers ofsilicon on a base semiconductor foundation, and other semiconductor oroptoelectronic materials, such as silicon-germanium, germanium, galliumarsenide, gallium nitride, and indium phosphide. The substrate 102 maybe doped or undoped. By way of non-limiting example, a substrate 102 maycomprise at least one of silicon, silicon dioxide, silicon with nativeoxide, silicon nitride, a carbon-containing silicon nitride, glass,semiconductor, metal oxide, metal, titanium nitride, carbon-containingtitanium nitride, tantalum, tantalum nitride, carbon-containing tantalumnitride, niobium, niobium nitride, carbon-containing niobium nitride,molybdenum, molybdenum nitride, carbon-containing molybdenum nitride,tungsten, tungsten nitride, carbon-containing tungsten nitride, copper,cobalt, nickel, iron, aluminum, and a noble metal.

The 2D material structure 104 is formed of and includes one or more 2Dmaterials. By way of non-limiting example, the 2D material structure 104may be formed of and include one or more of graphene; graphene-oxide;stanene; phosphorene; hexagonal boron nitride (h-BN); borophene;silicone; graphyne; germanene; germanane; a 2D supracrystal; atransition metal dichalcogenide (TMDC) having the general chemicalformula MX₂, wherein M is a transition metal (e.g., molybdenum (Mo),tungsten (W), niobium (Nb), zirconium (Zr), hafnium (Hf), rhenium (Re),platinum (Pt), titanium (Ti), tantalum (Ta), vanadium (V), cobalt (Co)cadmium (Cd), or chromium (Cr)) and X is a chalcogen (e.g., sulfur (S),selenium (Se), or tellurium (Te)); a carbide or carbonitride having thegeneral chemical formula M_(n+1)X_(n) (also referred to as an “MXene”)and including oxygen (—O), hydroxyl (—OH), or fluoro (—F) surfacetermination, wherein M is a transition metal from Groups IV or V of thePeriodic Table of Elements (e.g., Ti, Hf, Zr, V, Nb, Ta) and X isselected from carbon (C) and nitrogen (N); and a monolayer of a metalmaterial (e.g., palladium (Pd), rhodium (Rh)), a semi-metal material, ora semiconductive material. In some embodiments, the 2D materialstructure 104 is formed of and includes one or more TMDC monolayer(s),such as one or more monolayer(s) of MoS₂, MoSe₂, MoTe₂, WS₂, WSe₂, WTe₂,NbSe₂, ZrS₂, ZrSe₂, HfS₂, HfSe₂, and ReSe₂.

The 2D material structure 104 may include a single (e.g., only one) 2Dmaterial, or may include multiple (e.g., more than one) 2D materials. Byway of non-limiting example, the 2D material structure 104 may be formedof and include a stack of at least two different 2D materials. A firstof the 2D materials may be formed on or over the substrate 102, and asecond of the 2D materials may be formed on the first of the 2Dmaterials. In addition, one or more additional 2D materials may,optionally, be formed on or over the second of the 2D materials. If the2D material structure 104 comprises a stack of different 2D materials,longitudinally adjacent 2D materials of the stack may be coupled to oneanother through one or more intermolecular forces, such as Van der Waalsforces (e.g., as opposed to intramolecular forces, such as covalentbonds). In some embodiments, the 2D material structure 104 is formed ofand includes only one 2D material. In additional embodiments, the 2Dmaterial structure 104 is formed of and includes more than one 2Dmaterial. While the 2D material structure 104 is illustrated in FIG. 1as a planar structure, in additional embodiments the 2D materialstructure 104 may exhibit a different structural configuration, such asa non-planar structure.

As described in further detail below, the 2D material structure 104exhibits reduced crystalline defects as compared to conventional 2Dmaterial structures having the same 2D material composition (e.g.,formed of and including the same 2D material(s)) but formed throughconventional processes. The 2D material structure 104 may, for example,exhibit a reduced density of interstitial defects and/or vacancy defectsas compared to conventional 2D material structures having the same 2Dmaterial composition. By way of non-limiting example, if the 2D materialstructure 104 is formed of and includes at least one TMDC having thegeneral chemical formula MX₂ (e.g., MoS₂, MoSe₂, MoTe₂, WS₂, WSe₂, WTe₂,NbSe₂, ZrS₂, ZrSe₂, HfS₂, HfSe₂, ReSe₂), the TMDC may have a reducednumber of one or more of X-interstitial defects, X-vacancy defects,M-interstitial defects, M-vacancy defects, MX-vacancy defects, andXX-vacancy defects as compared to a 2D material structure having thesame 2D material composition, but formed through a conventional process.The above-mentioned defects are collectively referred to herein ascrystalline defects. In some embodiments, the 2D material structure 104is formed of at least one TMDC at least exhibiting a reduced number ofX-interstitial and X-vacancy defects as compared to a 2D materialstructure formed of the at least one TMDC through a conventionalprocess. In additional embodiments, the 2D material structure 104 isformed of and includes at least one 2D material substantially free(e.g., completely free) of all crystalline defects.

The 2D material structure 104 may be formed on or over the substrate 102by forming (e.g., growing, depositing) at least one 2D material on orover the substrate 102, and subjecting the 2D material to at least onelaser treatment process employing one or more selected frequencies ofelectromagnetic radiation corresponding to (e.g., the same as) one ormore resonant frequencies of crystalline defects of the 2D material.Exposing the 2D material to the selected frequencies of electromagneticradiation at least partially (e.g., substantially) eliminates thecrystalline defects from the 2D material. The selected frequencies ofradiation selectively energize, dissociate, and mobilize the crystallinedefects of the 2D material. The crystalline defects migrate (e.g.,diffuse) in-plane toward terminal ends (e.g., peripheral sides,peripheral edges) of the 2D material, where they may be removed from(e.g., eliminated from) the 2D material. In addition, as the crystallinedefects move across the 2D material, complementary defects (e.g.,oppositely charged defects) coming into geometric proximity to oneanother may be attracted to each other (e.g., by way of coulombicattraction) and interact to eliminate one another. For example, if the2D material comprises a TMDC, a mobile X-interstitial defect may beattracted to and interact with a mobile X-vacancy defect in closegeometric proximity thereto and eliminate both the X-interstitial defectand the X-vacancy defect, and/or a mobile M-interstitial defect may beattracted to and interact with a mobile M-vacancy defect in closegeometric proximity thereto and eliminate both the M-interstitial defectand the M-vacancy defect.

The at least one 2D material may formed on or over the substrate 102using one or more of a growth process and a deposition process. By wayof non-limiting example, the 2D material may be formed on or over thesubstrate 102 using one or more of an in situ growth process, a physicalvapor deposition (“PVD”) process, a chemical vapor deposition (“CVD”)process, a metallorganic chemical vapor deposition (“MOCVD”) process, aplasma-enhanced chemical vapor deposition (PECVD) process, an atomiclayer deposition (“ALD”) process, a spin-coating process, and a blanketcoating process. In situ growth processes include, but are not limitedto, epitaxial growth processes, such as atomic layer epitaxy (ALE),pulsed atomic layer epitaxy (PALE), molecular beam epitaxy (MBE), gassource MBE, organometallic MBE, and chemical beam epitaxy (CBE). PVDprocesses include, but are not limited to, one or more of sputtering,evaporation, and ionized PVD. The process utilized to form the 2Dmaterial on or over the substrate 102 may at least partially depend onthe material properties of the 2D material and the substrate 102, andmay affect the number (e.g., density) of crystalline defects present inthe 2D material. In some embodiments, the 2D material is formed on orover the substrate 102 using a CVD process.

The laser treatment process includes selecting at least one frequency ofelectromagnetic radiation to expose the at least one 2D material to, andexposing the 2D material to the selected frequency of electromagneticradiation. The frequency of electromagnetic radiation may be selected atleast partially based on a comparison of vibrational spectra for acrystalline-defect-free (e.g., perfect, pristine) form of the 2Dmaterial and a crystalline-defect-laden (e.g., imperfect, defective)form of the 2D material. Mutual resonant frequencies along thevibrational spectra (e.g., as compared by a vibrational differencespectrum) for the crystalline-defect-free form of the 2D material andthe crystalline-defect-laden form of the 2D material that do not exhibitsubstantial overlap between resonant peak intensities of thecrystalline-defect-free form of the 2D material and thecrystalline-defect-laden form of the 2D material identify frequencies ofelectromagnetic radiation that may be used to selectively energize,mobilize, and at least partially (e.g., substantially) eliminatecrystalline defects within the 2D material.

As a non-limiting example, FIG. 2 is a graph plotting vibrationalspectra for a crystalline-defect-free (“perfect”) form of MoS₂ and acrystalline-defect-laden (“defective”) form of MoS₂. As shown in FIG. 2,the graph identifies different resonant frequencies where the resonantpeak intensity of the crystalline-defect-laden form of MoS₂ issubstantially offset from (e.g., substantially different than) theresonant peak intensity of the crystalline-defect-free form of MoS₂. Forexample, the crystalline-defect-laden form of MoS₂ exhibits relativelyhigh resonant peak intensities at least at resonant frequencies of about224.3 cm′, about 345.1 cm⁻¹, and about 382.2 cm⁻¹, whereas thecrystalline-defect-free form of MoS₂ exhibits relatively low resonantpeak intensities at those resonant frequencies. Accordingly, based onthe vibrational spectra for the crystalline-defect-free form of MoS₂ andthe crystalline-defect-laden form of MoS₂, one or more of anelectromagnetic radiation frequency of about 224.3 cm⁻¹, anelectromagnetic radiation frequency of about 345.1 cm′, and anelectromagnetic radiation frequency of about 382.2 cm⁻¹ may, forexample, be selected to treat MoS₂ formed on or over the substrate 102to reduce a crystalline defect density of the MoS₂. Vibrational spectrafor crystalline-defect-free and crystalline-defect-laden forms of MoS₂may be different (e.g., resonant peaks may shift to differentvibrational frequencies) than those depicted in FIG. 2 depending, forexample, on the properties (e.g., material composition) of a substrate(e.g., the substrate 102) upon which the MoS₂ is formed. Nonetheless,even if, for a given underlying substrate, vibrational spectra forcrystalline-defect-free and crystalline-defect-laden forms of MoS₂ aredifferent than shown in FIG. 2, mutual resonant frequencies where theresonant peak intensity of a crystalline-defect-laden form of MoS₂ issubstantially different than the resonant peak intensity of acrystalline-defect-free form of MoS₂ identify frequencies ofelectromagnetic radiation that may be selected and used to treat MoS₂formed over the given substrate to reduce the number of crystallinedefects within the MoS₂.

A vibrational spectrum for the crystalline-defect-free form of the 2Dmaterial may be generated (e.g., calculated) using one or moreconventional modeling processes, such as one or more conventionalcomputational quantum mechanical modeling processes, which are notdescribed in detail herein. The modeling process may include geometryoptimization followed by vibrational analysis. By way of non-limitingexample, the vibrational spectrum for the crystalline-defect-free formof the 2D material may be calculated using a conventional densityfunctional theory (DFT) analysis process. The unit structure of the 2Dmaterial may be defined and analyzed to determine how thecrystalline-defect-free form of the 2D material would theoretically beformed on a given substrate. Computational analysis of thecrystalline-defect-free form of the 2D material may then be performed toevaluate resonance thereof at different vibrational frequencies anddevelop the vibrational spectrum thereof.

A vibrational spectrum for the crystalline-defect-laden form of the 2Dmaterial may be generated using one or more conventional vibrationalspectroscopy processes, such as one or more of a conventional infraredspectroscopy process and a conventional Raman spectroscopy process,which are not described in detail herein. An actual (e.g., non-modeled,non-theoretical) crystalline-defect-laden form of the 2D material may besubjected to a conventional vibrational spectroscopy process (e.g., aconventional 2D infrared spectroscopy process) to generate a vibrationalspectrum for the crystalline-defect-laden form of the 2D material thatmay be compared against a vibrational spectrum generated for thecrystalline-defect-free form of the 2D material through the conventionalcomputational quantum mechanical modeling process. Non-limitingexamples, of suitable vibrational spectroscopy processes for generatinga vibrational spectrum for the crystalline-defect-laden form of the 2Dmaterial include four-wave mixing processes and pump-probe processes(e.g., two-pulse photon echo processes, three-pulse photon echoprocesses, heterodyned four-wave mixing processes, homodyne four-wavemixing processes, dual-frequency heterodyned transient gratingprocesses, frequency resolved four-wave mixing processes, spectrallyresolved four-wave mixing processes, pulse shaping four-wave mixingprocesses, narrow band four-wave mixing processes, broad band four-wavemixing processes, time-gated four-wave mixing processes), six-wavemixing process, and eight-wave mixing processes. In additionalembodiments, a vibrational spectrum for the crystalline-defect-ladenform of the 2D material may be generated using one or more conventionalmodeling processes, such as one or more conventional computationalquantum mechanical modeling processes.

After selecting at least one frequency of electromagnetic radiation withwhich to expose the at least one 2D material, the 2D material may betreated with (e.g., exposed to, subjected to) the selected frequency ofelectromagnetic radiation using at least one laser source configured andoperated to generate one or more laser beams having the selectedfrequency of electromagnetic radiation. Any laser source capable ofgenerating and directing at least one laser beam having the selectedfrequency of electromagnetic radiation toward the 2D material may beemployed. By way of non-limiting example, the laser source may compriseone or more of a gas laser (e.g., a carbon monoxide (CO) laser; a carbondioxide (CO₂) laser), a semiconductor laser (e.g., a lead (Pb) saltsemiconductor laser; a quantum cascade laser (QCL)), and a solid-statelaser.

The selected frequency of electromagnetic radiation may be produced by asingle (e.g., only one) laser source, or may be produced by multiple(e.g., more than one) laser sources. If multiple laser sources areutilized, each of the multiple laser sources may be substantially thesame as one another and may produce substantially the same selectedfrequency of electromagnetic radiation, or at least one of the multiplelaser sources may be different than and/or produce a different selectedfrequency of electromagnetic radiation than at least one other of themultiple laser sources. In some embodiments, a single selected frequencyof electromagnetic radiation is produced by a single laser source. Inadditional embodiments, a single selected frequency of electromagneticradiation is produced by multiple laser sources. In further embodiments,multiple selected frequencies of radiation are produced by multiplelaser sources. If multiple laser sources are utilized, the multiplelaser sources may be used simultaneously, sequentially, or combinationsthereof. For example, one or more of the multiple laser sources may beused to treat the 2D material(s) with a first selected frequency ofelectromagnetic radiation corresponding to a first resonant frequencywhere resonant peak intensities of crystalline-defect-free andcrystalline-defect-laden forms of the 2D material(s) are different than(e.g., offset from) one another, and then one or more other of themultiple laser sources may subsequently be used to treat the 2Dmaterial(s) with a second selected frequency of electromagneticradiation corresponding to a second resonant frequency where resonantpeak intensities of the crystalline-defect-free and thecrystalline-defect-laden forms of the 2D material(s) are different thanone another. As another example, one or more of the multiple lasersources may be used to treat the 2D material(s) with a first selectedfrequency of electromagnetic radiation corresponding to a first resonantfrequency where resonant peak intensities of crystalline-defect-free andcrystalline-defect-laden forms of the 2D material(s) are different thanone another, and one or more other of the multiple laser sources may beused simultaneously with the one or more of the multiple laser sourcesto treat the 2D material(s) with a second selected frequency ofelectromagnetic radiation corresponding to a second resonant frequencywhere resonant peak intensities of the crystalline-defect-free and thecrystalline-defect-laden forms of the 2D material(s) are different thanone another.

The laser treatment process may employ any laser beam power(s) andduration(s) of exposure sufficient to reduce or even eliminate acrystalline defect density of the 2D material(s). The laser beampower(s) and duration(s) for a given application may at least partiallydepend on the electromagnetic radiation frequency (or frequencies)utilized, and the properties (e.g., material composition, dimensions) ofthe 2D material(s). An attenuator device may be used to control a laserbeam power level (e.g., intensity) at a surface of the 2D material(s) toa level facilitating selective energization, mobilization, and at leastpartial (e.g., substantial) elimination of crystalline defects withinthe 2D material(s). A laser beam power level at a surface of the 2Dmaterial(s) may, for example, be within a range of from about 1 Watt (W)to about 1000 W. In addition, a modulator device (e.g., anacousto-optical modulator device) may be used to control a duration oflaser beam exposure. A duration of laser beam exposure may, for example,be within a range of from about 1 millisecond (ms) to about 30 seconds(s).

The laser treatment process may expose the 2D material(s) to a single(e.g., only one) dose of one or more selected frequencies ofelectromagnetic radiation to form the 2D material structure 104 (FIG.1), or may expose the 2D material(s) to multiple doses of one or moreselected frequencies of radiation to form the 2D material structure 104.If multiple doses are utilized, an initial dose may partially reduce acrystalline defect density of the 2D material(s), and at least one otherdose may further reduce the crystalline defect density of the 2Dmaterial(s) to form the 2D material structure 104. Each of the multipledoses may be substantially the same (e.g., employ substantially the sameselected radiation frequency, power, and duration), or at least one ofthe multiple doses may be different than at least one other of themultiple doses (e.g., employ a different selected radiation frequency, adifferent power, and/or a different duration).

Exposing a 2D material to a selected frequency (or frequencies) ofelectromagnetic radiation corresponding to a specific resonant frequency(or frequencies) along the multidirectional vibrational spectra ofcrystalline-defect-free and crystalline-defect-laden forms of the 2Dmaterial exhibiting differences between respective resonant peakintensities facilitates a high degree of selectivity as to what types ofchemical bonds within the 2D material are modified using the radiation.When the 2D material is exposed to the selected frequency ofelectromagnetic radiation only chemical bonds that resonate at or nearthe selected frequency will be given the most energy by the radiation.The selected frequency of electromagnetic radiation may be absorbed bychemical bonds forming defective regions of (e.g., crystalline defectswithin) a 2D material, without being substantially absorbed by chemicalbonds forming non-defective regions of the 2D material, chemical bondsof the substrate 102 (FIG. 1), chemical bonds between the 2D materialand the substrate 102, and chemical bonds between the 2D material andanother 2D material (if any). Accordingly, the selected frequencies ofelectromagnetic radiation may selectively modify only the chemical bondsforming crystalline defects of the 2D material. Electromagneticradiation that is not absorbed by chemical bonds forming defectiveregions of the 2D material may be reflected or may be transmittedthrough the 2D material and the substrate 102. Consequently, using theselected frequencies of electromagnetic radiation to reduce thecrystalline defect density of the 2D material may generate little to noheat in areas of the 2D material (and the substrate 102) not proximatethe chemical bonds that the electromagnetic radiation has been selectedto resonate with. By controlling the generation and use of heat insemiconductor device manufacturing, introduction of thermal defects canbe avoided, and low-temperature manufacturing techniques can be moreeasily achieved.

Thus, in accordance with embodiments of the disclosure, a method offorming a semiconductor device structure comprises forming at least one2D material over a substrate. The at least one 2D material is treatedwith at least one laser beam having a frequency of electromagneticradiation corresponding to a resonant frequency of crystalline defectswithin the at least one 2D material to selectively energize and removethe crystalline defects from the at least one 2D material.

In addition, in accordance with additional embodiments of thedisclosure, another method of forming a semiconductor device structurecomprises subjecting a 2D material on a substrate to a laser treatmentprocess to reduce a crystalline defect density of the 2D material. Thelaser treatment process comprises exposing the 2D material to at leastone frequency of electromagnetic radiation substantially the same as atleast one resonant frequency of crystalline-defect-free andcrystalline-defect-laden forms of the 2D material where resonant peakintensities of the crystalline-defect-free and crystalline-defect-ladenforms of the 2D material are different than one another.

In some embodiments, a thermal annealing process may be used inconjunction with the laser treatment process to facilitate or enhance areduction in the crystalline defect density of the 2D material(s) andform the 2D material structure 104 (FIG. 1). If employed, the thermalannealing process may heat the 2D material(s) to a temperature greaterthan a formation (e.g., growth, deposition) temperature of the 2Dmaterial(s) to raise a ground state of all atoms and crystalline defectsand increase a rate of diffusion of the crystalline defects out of the2D material(s). By way of non-limiting example, if the 2D material(e.g., MoS₂) is formed at a temperature less than or equal to about 225°C., the thermal annealing process may subject the 2D material to atemperature greater than about 225° C. (e.g., greater than or equal toabout 250° C., greater than or equal to about 300° C., or greater thanor equal to about 400° C.) to raise a ground state of all atoms (e.g.,Mo atoms, S atoms) and crystalline defects (e.g., S-interstitialdefects, S-vacancy defects, Mo-interstitial defects, Mo-vacancy defects,MoS-vacancy defects, and SS-vacancy defects) and increase a rate ofdiffusion of the crystalline defects out of the 2D material(s) duringthe laser treatment process. Suitable thermal annealing processesinclude, but are not limited to, furnace annealing processes, chamberannealing processes, and laser annealing processes. In additionalembodiments, the laser treatment process may be performed withoutperforming a thermal annealing process in conjunction therewith. Infurther embodiments, one or more of a magnetic field, an electricalfield, a bias, or a combination thereof, may be employed to increase therate of diffusion of the crystalline defects out of the 2D material(s).

The 2D material(s) may be subjected to the laser treatment process andthe thermal annealing process (if any) during the formation (e.g.,deposition, growth) of the 2D material(s) on or over the substrate 102,after the formation of the 2D material(s) on or over the substrate 102,or a combination thereof. If a thermal annealing process is employed inconjunction with the laser treatment process, the laser treatmentprocess and the thermal annealing process may be performed in any order,and with any amount of temporal overlap therebetween. The lasertreatment process and the thermal annealing process (if any) may beperformed simultaneously, sequentially, or a combination thereof. Inaddition, there is no limit to the number of times a laser treatmentprocess and/or a thermal annealing process can be performed.Accordingly, one or more of the laser treatment process and the thermalannealing process (if any) may be performed multiple times, and notnecessarily in the same order nor with the same temporal overlap foreach repetition of the laser treatment process and the thermal annealingprocess (if any).

In some embodiments, at least one 2D material is subjected to the lasertreatment process during the formation of the 2D material on or over thesubstrate 102 to selectively energize, mobilize, and at least partially(e.g., substantially) eliminate crystalline defects within the 2Dmaterial. In addition, the laser treatment process is performed withoutperforming the thermal annealing process concurrent therewith. Putanother way, the 2D material is subjected to the laser treatment processwithout using a separate thermal annealing process (e.g., a furnaceannealing process, a chamber annealing process, a laser annealingprocess) to heat the 2D material to a temperature greater than aformation temperature thereof. In such embodiments, heat supplied by theprocess (e.g., deposition process, growth process) used to form the 2Dmaterial may, by itself, be sufficient to raise a ground state of allatoms and crystalline defects of the 2D material and facilitate adesirable rate of diffusion of the crystalline defects out of the 2Dmaterial.

In additional embodiments, at least one 2D material is subjected to thelaser treatment process and the thermal annealing process during theformation of the 2D material on or over the substrate 102 to selectivelyenergize, mobilize, and at least partially (e.g., substantially)eliminate crystalline defects within the 2D material. The thermalannealing process (e.g., furnace annealing process, chamber annealingprocess, laser annealing process) is performed concurrent with the lasertreatment process. The thermal annealing process is employed to heat the2D material to a temperature greater than that which would otherwise beachieved by the heat supplied by the process (e.g., deposition process,growth process) used to form the 2D material alone. The separate thermalannealing process raises a ground state of all atoms and crystallinedefects of the 2D material to increase the rate of diffusion of thecrystalline defects out of the 2D material during the formation thereof.

In yet additional embodiments, at least one 2D material is formed on orover the substrate 102, and is then subjected to the laser treatmentprocess and the thermal annealing process to selectively energize,mobilize, and at least partially (e.g., substantially) eliminatecrystalline defects within the 2D material. Put another way, the lasertreatment process and the thermal annealing process are each performedonly after the 2D material has already been formed (e.g., deposited,grown) on or over the substrate 102. The laser treatment process and thethermal annealing process may, for example, be used to repair the 2Dmaterial after an intervening period of time has passed subsequent tothe formation of the 2D material. The 2D material may have cooled from aformation temperature thereof during the intervening period of time. Thethermal annealing process (e.g., furnace annealing process, chamberannealing process, laser annealing process) is performed concurrent withthe laser treatment process. The thermal annealing process raises aground state of all atoms and crystalline defects of the 2D material toincrease the rate of diffusion of the crystalline defects out of the 2Dmaterial during the concurrent laser treatment process.

In further embodiments, at least one 2D material is formed on or overthe substrate 102, the formed 2D material is then subjected to thermalannealing process, and then the thermally treated 2D material issubjected to the laser treatment process to selectively energize,mobilize, and at least partially (e.g., substantially) eliminatecrystalline defects within the thermally treated 2D material. Putanother way, the thermal annealing process is performed only after the2D material has already been formed (e.g., deposited, grown) on or overthe substrate 102, and the laser treatment process is performed afterthe thermal annealing process. The sequence of the thermal annealingprocess and the laser treatment process may, for example, be used torepair the 2D material after an intervening period of time has passedsubsequent to the formation of the 2D material. The 2D material may havecooled from a formation temperature thereof during the interveningperiod of time. The thermal annealing process raises a ground state ofall atoms and crystalline defects of the 2D material to increase therate of diffusion of the crystalline defects out of the 2D materialduring the subsequent laser treatment process.

In yet further embodiments, at least one 2D material is formed on orover the substrate 102, the formed 2D material is then subjected to thelaser treatment process, and then the laser treated 2D material issubjected to the thermal annealing process. Put another way, the lasertreatment process is performed only after the 2D material has alreadybeen formed (e.g., deposited, grown) on or over the substrate 102, andthe thermal annealing process is performed after the laser treatmentprocess. The sequence of the laser treatment process and the thermalannealing process may, for example, be used to repair the 2D materialafter an intervening period of time has passed subsequent to theformation of the 2D material. The 2D material may have cooled from aformation temperature thereof during the intervening period of time. Insome embodiments, the thermal annealing process is effectuated after thestart of but prior to the completion of the laser treatment process, andraises a ground state of all atoms and crystalline defects of the 2Dmaterial to increase the rate of diffusion of the crystalline defectsout of the 2D material during the remainder of the laser treatmentprocess. In additional embodiments, the thermal annealing process iseffectuated after the completion of the laser treatment process.

In addition, a remote plasma treatment process may be used inconjunction with at least the laser treatment process (and the thermaltreatment process, if any) to promote the formation of the 2D materialstructure 104 (FIG. 1). The remote plasma treatment process may, forexample, be used to treat a surface of one or more 2D material(s) topromote the formation of one or more additional 2D material(s) thereonor thereover. The remote plasma treatment process may promote nucleationof the additional 2D material(s) on or over the surface(s) of the 2Dmaterial(s). If employed, the remote plasma treatment process may beperformed after the formation of a 2D material on or over the substrate102. The remote plasma treatment process may, for example, be performedafter at least the laser treatment process (and the thermal treatmentprocess, if any) of the 2D material on or over the substrate 102.

With continued reference to FIG. 1, following the formation of the 2Dmaterial structure 104, the semiconductor device structure 100 includingthe 2D material structure 104 may be subjected to additional processing(e.g., material removal processes, additional deposition processes), asdesired. The additional processing may be conducted using conventionalprocesses and conventional processing equipment, and is not illustratedor described in detail herein.

Semiconductor device structures (e.g., the semiconductor devicestructure 100) formed in accordance with embodiments of the disclosuremay be used in various semiconductor devices including, but not limitedto, memory (e.g., random access memory (ROM), read only memory (ROM)),transistors (e.g., field-effect transistors (FETs), thin filmtransistors (TFTs), bipolar transistors), diodes, inverters, logicgates, junctions, photodetectors, photovoltaic cells, light-emittingdiodes (LEDs), electronic sensors, integrated circuits, andmicroprocessors. By way of non-limiting example, semiconductor devicestructures formed in accordance with embodiments of the disclosure maybe used in various FETs including, but not limited to, tunnelfield-effect transistors (TFETs) (e.g., single gate TFETs, double gateTFETs, lateral TFETs, vertical TFETs, synthetic electric field TFETs(SE-TFETs)), and vertical FETs (VFETs). The 2D material structures(e.g., 2D material structure 104) of the semiconductor device structures(e.g., the semiconductor device structure 100) formed in accordance withembodiments of the disclosure may, for example, be employed as channelsof the FETs.

In addition, semiconductor devices (e.g., memory, transistors, diodes,inverters, logic gates, junctions, photodetectors, photovoltaic cells,LEDs, electronic sensors, integrated circuits, microprocessors) formedin accordance with embodiments of the disclosure may be included invarious electronic systems. By way of non-limiting example, FIG. 3 is ablock diagram of an electronic system 300 according to embodiments ofdisclosure. The electronic system 300 may comprise, for example, acomputer or computer hardware component, a server or other networkinghardware component, a cellular telephone, a digital camera, a personaldigital assistant (PDA), a portable media (e.g., music) player, a WiFior cellular-enabled tablet such as, for example, an iPad® or SURFACE®tablet, an electronic book, a navigation device, etc. The electronicsystem 300 includes at least one memory device 302. The at least onememory device 302 may include, for example, an embodiment of thesemiconductor device structure 100 shown in FIG. 1. The electronicsystem 300 may further include at least one electronic signal processordevice 304 (e.g., microprocessor). The electronic signal processordevice 304 may, optionally, include a semiconductor device structuresimilar to an embodiment of the semiconductor device structure 100 shownin FIG. 1. The electronic system 300 may further include one or moreinput devices 306 for inputting information into the electronic system300 by a user, such as, for example, a mouse or other pointing device, akeyboard, a touchpad, a button, or a control panel. The electronicsystem 300 may further include one or more output devices 308 foroutputting information (e.g., visual or audio output) to a user such as,for example, a monitor, a display, a printer, an audio output jack, aspeaker, etc. In some embodiments, the input device 306 and the outputdevice 308 may comprise a single touchscreen device that can be usedboth to input information to the electronic system 300 and to outputvisual information to a user. The one or more input devices 306 andoutput devices 308 may communicate electrically with at least one of thememory device 302 and the electronic signal processor device 304.

Thus, a semiconductor device according to embodiments of the disclosurecomprises at least one semiconductor device structure comprising a 2Dmaterial structure overlying a substrate and comprising a 2D materialsubstantially free of interstitial defects and vacancy defects.

Furthermore, an electronic system according to embodiments of thedisclosure comprises at least one semiconductor device and peripheralcircuitry electrically connected to the at least one semiconductordevice. The at least one semiconductor device includes at least onesemiconductor device structure comprising a substrate, and a 2D materialstructure over the substrate and comprising one or more 2D materialssubstantially free of crystalline defects.

The methods of the disclosure may effectively reduce crystalline defects(e.g., interstitial defects, vacancy defects) in one or more 2Dmaterial(s) to facilitate the formation of semiconductor devicestructures (e.g., the semiconductor device structure 100) havingimproved electrical properties as compared to conventional semiconductordevice structures not formed in accordance with embodiments of thedisclosure. The laser treatment processes of the disclosure may reducecrystalline defect densities of the 2D material(s) while avoidingundesirable changes (e.g., undesirable structural deformations,undesirable material diffusion) to the 2D material(s) and/or otherstructures (e.g., the substrate 102) operatively associated therewith(e.g., bound thereto). Semiconductor device structures (e.g., thesemiconductor device structure 100) according to embodiments ofdisclosure may, in turn, improve one or more properties of devices intowhich they are at least partially incorporated. Semiconductor devicesand electronic systems including semiconductor device structures formedusing the methods of the disclosure may have enhanced performance,reliability, and durability as compared to many conventionalsemiconductor devices and electronic systems.

While the disclosure is susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, the disclosure is not limited to the particular formsdisclosed. Rather, the disclosure is to cover all modifications,equivalents, and alternatives falling within the scope of the followingappended claims and their legal equivalents.

1. An electronic system, comprising: at least one semiconductor deviceincluding at least one semiconductor device structure comprising: a 2Dmaterial structure comprising a stack including substantiallycrystalline-defect-free forms of two or more of at least one carbide andat least one carbonitride having the general chemical formulaM_(n+1)X_(n), where: M is a transition metal from Group IV or Group V ofthe Periodic Table of Elements; and X is one or more of C and N; andperipheral circuitry electrically connected to the at least onesemiconductor device.
 2. The electronic system of claim 1, wherein M isTi, Hf, Zr, V, Nb, or Ta.
 3. The electronic system of claim 1, wherein:the stack includes the at least one carbide; and the at least onecarbide comprises at least two carbides.
 4. The electronic system ofclaim 1, wherein: the stack includes the at least one carbonitride; andthe at least one carbonitride comprises at least two carbonitrides. 5.The electronic system of claim 1, wherein the stack includes the atleast one carbide and the at least one carbonitride.
 6. The electronicsystem of claim 1, wherein the 2D material structure further comprises asubstantially crystalline-defect-free form of at least one transitionmetal dichalcogenide having the general chemical formula AY₂, where: Ais Mo, W, Nb, Zr, Hf, Re, Pt, Ti, Ta, V, Co, Cd, or Cr; and Y is S, Se,or Te.
 7. The electronic system of claim 6, wherein the at least onetransition metal dichalcogenide is selected from MoS₂, MoSe₂, MoTe₂,WS₂, WSe₂, WTe₂, NbSe₂, ZrS₂, ZrSe₂, HfS₂, HfSe₂, and ReSe₂.
 8. Theelectronic system of claim 7, the at least one transition metaldichalcogenide comprises MoS₂.
 9. The electronic system of claim 1,wherein the 2D material structure further comprises one or more ofgraphene, graphene-oxide, stanene, phosphorene, hexagonal boron nitride,borophene, silicene, graphyne, germanene, and germanane.
 10. Theelectronic system of claim 1, wherein the 2D material structure incudesone of oxygen surface termination, hydroxyl surface termination, andfluoro surface termination.
 11. An electronic system, comprising: aninput device; an output device; a processor device operably coupled tothe input device and the output device; and a memory device operablycoupled to the processor device and including a stack structurecomprising adjacent substantially crystalline-defect-free 2D materials,at least two of the adjacent substantially crystalline-defect-free 2Dmaterials having different material compositions than one another andindividually selected from at least one carbide and at least onecarbonitride having the general chemical formula M_(n+1)X_(n), where: Mis Ti, Hf, Zr, V, Nb, or Ta; and X is one or more of C and N.
 12. Theelectronic system of claim 11, wherein the memory device is selectedfrom a random access memory device and a read only memory device. 13.The electronic system of claim 11, wherein the stack structure isincluded within a transistor of the memory device.
 14. The electronicsystem of claim 11, wherein the memory device further includes a basestructure adjacent the stack structure, the base structure comprisingone or more of silicon, silicon dioxide, silicon with native oxide,silicon nitride, a carbon-containing silicon nitride, glass,semiconductor, metal oxide, metal, titanium nitride, carbon-containingtitanium nitride, tantalum, tantalum nitride, carbon-containing tantalumnitride, niobium, niobium nitride, carbon-containing niobium nitride,molybdenum, molybdenum nitride, carbon-containing molybdenum nitride,tungsten, tungsten nitride, carbon-containing tungsten nitride, copper,cobalt, nickel, iron, aluminum, and a noble metal.
 15. The electronicsystem of claim 11, wherein the adjacent substantiallycrystalline-defect-free 2D materials further comprise one or moremonolayers of one or more of graphene, graphene-oxide, stanene,phosphorene, hexagonal boron nitride, borophene, silicene, graphyne,germanene, germanane, 2D supracrystal, MoS₂, MoSe₂, MoTe₂, WS₂, WSe₂,WTe₂, NbSe₂, ZrS₂, ZrSe₂, HfS₂, HfSe₂, and ReSe₂.
 16. The electronicsystem of claim 11, wherein stack structure has oxygen surfacetermination, hydroxyl surface termination, or fluoro surfacetermination.
 17. An electronic system, comprising: an input device; anoutput device; a processor device operably coupled to the input deviceand the output device; and a memory device operably coupled to theprocessor device and including at least one transistor having a channelincluding a stack of 2D materials substantially free of crystallinedefects, at least two of the 2D materials individually having thegeneral chemical formula M_(n+1)X_(n), where: M is a transition metalfrom Group IV or Group V of the Periodic Table of Elements; and X is oneor more of C and N.
 18. The electronic system of claim 17, wherein M isselected from Ti, Hf, Zr, V, Nb, and Ta.
 19. The electronic system ofclaim 17, wherein the stack of 2D materials further comprises one ormore monolayers of one or more of MoS₂, MoSe₂, MoTe₂, WS₂, WSe₂, WTe₂,NbSe₂, ZrS₂, ZrSe₂, HfS₂, HfSe₂, and ReSe₂.
 20. The electronic system ofclaim 17, wherein the stack of 2D materials further comprises one ormore monolayers of one or more of metal material, semi-metal material,and semiconductive material.